Antarctica ‘intimately coupled’ with future of rest of planet

Next decade critical to Antarctica’s fate and consequences for Earth, scientists warn

Icebergs in the northern Weddell Sea off Antarctica:  ice loss is speeding up and adding even more to rising sea levels. Photograph: John Sonntag/Nasa via The New York Times

Icebergs in the northern Weddell Sea off Antarctica: ice loss is speeding up and adding even more to rising sea levels. Photograph: John Sonntag/Nasa via The New York Times

 

It may be the remotest region in the world but Antarctica is “intimately coupled” with the rest of the planet and human society, according to a group of eminent scientists.

The next decade will be critical to Antarctica’s fate as choices made in that period will have long-lasting consequences across Earth, they predict.

Two different “plausible future scenarios” for the continent are outlined; one leading to irreversible changes and the other successfully countering the worst effects of global warming.

Recent work by Prof Rob DeConto of the University of Massachusetts Amherst in the US highlighted the potential for Antarctica to contribute much more sea-level rise in the world’s oceans than previously considered.

But it also showed how reduced greenhouse gas (GHG) emissions could reduce the exposure of low-lying coastlines and cities to rising seas.

In a Nature paper this week, he says: “A reduction in emissions, in line with the aspirations of the Paris Climate Agreement, dramatically reduces the risk of flooding our coastlines in future decades and centuries.”

Ice shelves

He and eight co-authors accept their scenarios are “highly speculative”. They are “not forecasts but intended as starting points for discussion”. They touch on consequences for ice shelves, invasive species, ocean and land ecosystems, and humans.

In the first scenario, “GHG emissions remained unchecked, the climate continued to warm” and the policy responses were ineffective with large ramifications in Antarctica and worldwide. Antarctica and the Southern Ocean would see dramatic loss of ice shelves, causing an acceleration in global sea-level rise.

In the second scenario, “ambitious action” has been taken to limit emissions and to establish policies that reduce human pressure on the environment, slowing the rate of change and enhancing Antarctica’s resilience. It would look “much like it did in the early decades of the century”, with slower loss from the ice sheet and reduced threat of sea level rise.

“GHG emissions must start decreasing in the coming decade to have a realistic prospect of following the low emissions narrative and so avoid global impacts,” said co-author Dr Steve Rintoul. “Actions can be taken now that will slow the rate of environmental change, increase the resilience of Antarctica, and reduce the risk we commit to irreversible changes with widespread impact.”